An access independent part of any network is known as a core network. In mobile communications networks a core network typically includes a mobile switching center, a packet data network, and other network entities. In other types of networks, similar network entities are present and perform various tasks such as routing communications and establishing packet sessions. An access dependent as routing communications and establishing packet sessions. An access dependent part of a network is known as an access network (AN). In wireless communications networks, an AN is known as a radio access network (RAN) which includes a radio network controller (RNC) or base station controller (BSC) and base stations or Node Bs. A RAN manages wireless communications links with user equipment (UE), sometimes called mobile stations (MS). Meanwhile, a CN manages communications links to fixed networks and mobile networks. Examples of fixed networks include a public-switched telephone network (PSTN), an Integrated Services Digital Network (ISDN), and the Internet. An example of a mobile network is a Public Land Mobile Network (PLMN). Often mobile networks are interconnected to fixed networks. The CN receives messages from a public switched telephone network (PSTN), mobile stations, and other core networks and core network entities.
In current mobile communications networks, the RAN and the CN are configured such that one radio access network is connected to only one core network. One RAN can be identified by one or more broadcasted identities. One CN is typically operated by one network operator and, for purposes such as routing, identified by one or more network identities.
A wireless communications system is coupled to other communications networks; each system typically operated by one operator or carrier. This type of system is currently used for GSM, CDMA, and TDMA type networks for example, and each system operator generally uses one type of network, e.g., either CDMA or GSM or TDMA. Each wireless communications system operates on an assigned frequency band because there are only a finite number of available frequencies. With the current systems, one system operator typically operates both the RAN and the core network. The RAN broadcasts a message that includes an identifier for the core network coupled to the RAN. The number of system operators is limited to the number of frequency licenses available for communications systems in a given area.
In current networks such as GSM, UMTS and CDMA2000, the RAN can be connected to one CN. This means that the RAN and the CN are able to use the same PLMN identity, where the PLMN identity is broadcast by the RAN and identifies the network. This means that when the mobile station selects the RAN, no separate selection of a CN operator needs to occur.
Emerging wireless communications technologies allows network operators to share resources. One example of network sharing is to share the radio access network resources by allowing multiple core networks operated typically by different operators to couple to a radio network controller (RNC) which controls the radio resources. This allows multiple service providers to use the same limited number of frequency bands. However, the RNC now must accommodate multiple system operators to ensure that the information from a MS is directed to the proper system operator or service provider. In the emerging universal mobile telephone system (UMTS), the routing of messages to one of many core networks, is limited on the basis of core network domain type (i.e., packet switched or circuit switched) and not by system operator, since there is only one system operator typically for both the radio network and the core network. In a shared RAN, however, multiple core network operators share the radio infrastructure and/or radio frequencies. Thus the RAN is now associated with multiple PLMN identities, i.e. core network operators.
Thus, there is a desire to allow UEs efficient access to the available PLMNs to provide wireless communications. Additionally, it is desirable to distribute user equipment equitably across the shared network to reduce traffic congestion and effectively allocate resources.
The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Drawings and accompanying Detailed Description.